Willoughby J O, Fitzgibbon S P, Pope K J, Mackenzie L, Medvedev A V, Clark C R, Davey M P, Wilcox R A
Centre for Neuroscience and Department of Medicine (Neurology), Flinders University, PO Box 2100, Adelaide, South Australia, Australia 5001.
J Neurol Neurosurg Psychiatry. 2003 Jan;74(1):51-5. doi: 10.1136/jnnp.74.1.51.
Gamma oscillations (30-100 Hz gamma electroencephalographic (EEG) activity) correlate with high frequency synchronous rhythmic bursting in assemblies of cerebral neurons participating in aspects of consciousness. Previous studies in a kainic acid animal model of epilepsy revealed increased intensity of gamma rhythms in background EEG preceding epileptiform discharges, leading the authors to test for intensified gamma EEG in humans with epilepsy.
64 channel cortical EEG were recorded from 10 people with primary generalised epilepsy, 11 with partial epilepsy, and 20 controls during a quiescent mental state. Using standard methods of EEG analysis the strength of EEG rhythms (fast Fourier transformation) was quantified and the strengths of rhythms in the patient groups compared with with controls by unpaired t test at 1 Hz intervals from 1 Hz to 100 Hz.
In patients with generalised epilepsy, there was a threefold to sevenfold increase in power of gamma EEG between 30 Hz and 100 Hz (p<0.01). Analysis of three unmedicated patients with primary generalised epilepsies revealed an additional 10-fold narrow band increase of power around 35 Hz-40 Hz (p<0.0001). There were no corresponding changes in patients with partial epilepsy.
Increased gamma EEG is probably a marker of the underlying ion channel or neurotransmitter receptor dysfunction in primary generalised epilepsies and may also be a pathophysiological prerequisite for the development of seizures. The finding provides a new diagnostic approach and also links the pathophysiology of generalised epilepsies to emerging concepts of neuronal correlates of consciousness.
伽马振荡（30 - 100赫兹的伽马脑电图（EEG）活动）与参与意识相关方面的大脑神经元集合中的高频同步节律性爆发相关。先前在癫痫的 kainic 酸动物模型中的研究表明，癫痫样放电之前背景脑电图中伽马节律的强度增加，这促使作者对癫痫患者的伽马脑电图增强情况进行测试。
在安静的精神状态下，记录了10名原发性全身性癫痫患者、11名部分性癫痫患者和20名对照者的64通道皮层脑电图。使用脑电图分析的标准方法（快速傅里叶变换）对脑电图节律的强度进行量化，并通过未配对 t 检验，以1赫兹的间隔从1赫兹到100赫兹，将患者组的节律强度与对照组进行比较。
在全身性癫痫患者中，30赫兹至100赫兹之间的伽马脑电图功率增加了三至七倍（p<0.01）。对三名未用药的原发性全身性癫痫患者的分析显示，在35赫兹至40赫兹左右，功率还有额外的10倍窄带增加（p<0.0001）。部分性癫痫患者没有相应变化。
伽马脑电图增加可能是原发性全身性癫痫潜在离子通道或神经递质受体功能障碍的标志，也可能是癫痫发作发展的病理生理前提。这一发现提供了一种新的诊断方法，也将全身性癫痫的病理生理学与意识的神经元相关新观念联系起来。
